SUMMARY -Eighty untreated patients suspected to have leprosy were submitted to neuro¬ physiological examination and later compared with the clinical diagnosis. Among the patients who had leprosy confirmed, 98% had EMG abnormalities.Motor and sensory amplitude reduction was the earliest and the most frequent abnormality. Low conduction velocity of the ulnar nerve across the elbow was present in over 55% ot the patients.A «mosaic» peripheral polyneuropathy was the most characteristic finding, and seems to be helpful to the diagnosis of leprosy. All of the clinical forms showed BMG abnormalities, and even some asymptomatic contacts, however the abnormalities increase from ;he indetermined and tuberculous to the borderline and Virchow's forms.Diagnóstico eletromiográfico da lepra.RESUMO -Hanseníase tem sido considerada doença dermatológica, embora semprt provoque lesões de nervos periféricos e nem sempre provoque lesões dermatológicas.O diagnóstico de hanseníase jamais seria considerado sem alterações sensitivas.Partindo desse princípio, 80 pacientes com suspeita de hanseníase, não tratados anteriormente, foram submetidos a cuidadoso exame eletrofisiológico na busca de lesões de nervos periféricos. Cerca de 98% dos paciente» em que hanseníase foi confirmada pelos métodos tradicionais apresentaram alterações eletromiográficas.O achado mais comum e precoce foi redução da amplitude das respostas motoras e sensitivas, usualmente duas vezes mais freqüente que redução nas velocidades de condução nervosa no mesmo nervo.O nervo mais freqüentemente alterado foi o ulnar, em que a amplitude sensitiva estava reduzida em 62% dos pacientes e a velocidade de condução nervosa sensitiva em apenas 29%. A velocidade de condução nervosa motora do nervo ulnar no canal cubital estava reduzida em 55% dos pacientes (síndrome do túnel cubital).Síndrome do túnel carpiano foi observada em 16% dos pacientes. Alterações eletromiográficas foram registradas em todas as formas clínicas, discretas na forma indeterminada, moderadas na forma tuberculóide e severas nas formas dimorfa e virchowiana. Surpreendentemente, alguns contatos assintomáticos apresentaram alterações eletromiográficas, mais freqüentemente a síndrome do túnel cubital, o que sugere a possibilidade de uma «cicatriz» neurofisiológica: o «complexo primário» da hanseníase.Alguns desses contatos poderiam ainda pertencer à forma I, incipiente. Juntamente com a síndrome do túnel cubital e a redução da amplitude sensitiva no território do nervo ulnar, distribuição em «mosaico» das lesões nervosas foi o achado mais característico da hanseníase (polineuropatia em mosaico). Nossos achados evidenciam a utilidade da eletromiografia no diagnóstico da hanseníase, em qualquer estágio ou forma, particularmente nos estágios iniciais, quando os testes atualmente em uso são ineficientes.Although leprosy always produces peripheral nerve damage, it remains the concept of dermatological disease.A systematic and prospective neurophysiological study of peripheral nerve involvement in leprosy has not been p...

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S U M M ARY The number of motor units in a muscle, the abductor pollicis longus (APL), supplied by the radial nerve was estimated. In 40 APL muscles of control subjects, the mean number of motor units was found to be 421±99 (SD). Ten patients underwent conventional EMG examination to confirm the clinical suspicion of denervation in radial nerve territory. All presented a significant reduction in the number of motor units in the APL muscle. These results show that this method is useful in the evaluation of muscles supplied by the radial nerve.A quantal method was described by McComas et al. (1971) for estimating the number of functioning motor units within a human muscle. Weak stimuli of increasing intensity were applied to the nerve innervating the muscle, and the summated electrical responses of single motor units were then compared with the maximum evoked muscular response. An investigation of the number of the motor units in one of the muscles innervated by the radial nerve has not been undertaken previously. The abductor pollicis longus (APL) was chosen because of its relatively isolated and superficial position among the muscles of the forearm. These conditions have permitted the recording of the action potentials without significant interference from other muscles supplied by the radial nerve. MethodsForty APL muscles were studied in 26 healthy subjects of both sexes who were aged between 16 and 43 years and had no evidence of neurological abnormalities. In addition, 10 patients suspected of having denervation of APL were studied; two of these had motor neurone disease, three had radial nerve palsies, three had cervical radiculopathies, and two had brachial neuropathy. In each case, the ambient temperature was regulated at 22-240C and the subjects were examined on a couch with the arm pronated.Address for reprint requests: Dr C. R. DeFaria, Instituto de Neurologia de Goiania, CP 157, 74 000 Goiania, Goias, Brazil. Accepted 23 February 1978 Surface electrodes were used for nerve stimulation and for recording muscle responses. The stimulating electrodes were chlorided silver convex discs, 10 mm in diameter, which were mounted in a Plexiglass holder so that their centres were 30 mm apart. The recording electrodes were constructed out of 6 mm wide silver foil; the stigmatic and reference electrodes were 22 mm in length while the earth (ground) electrode measured 60 mm. The electrodes were coated with a conducting jelly, and the stigmatic electrode was placed so as to cover the endplate zone, which was found to lie transversely across the muscle some 70 mm proximal to the styloid process of the radius (Fig. 1)

RESUMO -Técnicas de neurofisiologia clínica aplicadas em 41 pacientes com as várias formas clínicas da doença de Chagas demonstraram haver correlação entre as formas clínicas da doença e a intensidade da desnervação muscular periférica.Os pacientes com a forma cárdio-digestiva mostraram intensa desnervação; aqueles das formas cardíaca e digestiva (puras), moderada desnervação; os da forma indeterminada, discreta desnervação. Neuropatia periférica tipo axonal foi observada acompanhando a mesma distribuição da desnervação de músculos esqueléticos (motora). Já a intensidade da desnervação não mostrou relação direta com a gravidade das manifestações clínicas. Peripheral denervation among the different clinical forms of Chagas' disease.SUMMARY -EMG examination was performed in 41 patients with Chagas' disease, belonging to the several clinical forms of the disease.Constant and direct relationship between the amount of muscle skeletal denervation and the clinical forms has been shown.In addition light peripheral axonal neuropathy was seen.Both muscular and sensory denervation was intense in the group with cardio-digestive form, moderate in the groups with either cardiac or digestive form and light in the group with the indeterminate form.The severity of the clinical symptoms was not related with the amount of peripheral denervation. O interesse pelo comprometimento do sistema nervoso na doença de Chagas acompanha sua história.Chagas, em seus primeiros trabalhos, referiu-se a várias manifestações neurológicas em seus pacientes, tendo inclusive suspeitado de uma forma nervosa da doença. Em 1909, observou predomínio de envolvimento do sistema nervoso central na fase aguda da doença em pacientes jovens, notadamente em crianças abaixo de um ano, nas quais o óbito por manifestações meningoencefálicas era predominante 7. Torres e Vilaça 31, em 1919, demonstraram lesões focais e difusas no cérebro, cerebelo e medula espinhal de cães experimentalmente infectados pelo T. cruzi, com predomínio de lesões na substância branca.Estes achados foram confirmados por Villela e Torres 33 que observaram ainda ser a forma aguda da tripanosomíase causadora de forma nervosa grave, quase sempre fatal em cães jovens, confirmando experimentalmente as observações de Chagas 7 .Chagas e Villela 8 já se referiam a "influências nervosas defeituosas" para explicar perturbações cardíacas e ainda relacionaram a bradicardia ao "mal do engasgo", numa clara referência do envolvimento do sistema nervoso no quadro clínico da doença; neste trabalho a fraqueza e as dores nas pernas foram registradas, apontando um problema que só agora, com os estudos neurofisiológicos começa a ser explicado.

Neurophysiological examination before and after the administration of benzonidazole, has shown peripheral polyneuropathy induced by this drug in most of the patients treated for chronic Chagas' disease. The polyneuropathy was mostly axonal and it was dose dependent being more severe in patients who had denervation of skeletal muscles before receiving the drug.